1. Field of the Invention
The present invention relates generally to heat exchangers for motor vehicles and, more specifically, to a beaded plate and method of making same for a heat exchanger in a motor vehicle.
2. Description of the Related Art
It is known to provide plates for a heat exchanger such as an oil cooler in a motor vehicle. Typically, opposed plates carry a first fluid medium in contact with an interior thereof while a second fluid medium contacts an exterior thereof. Typically, the first fluid medium is oil and the second fluid medium is water. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the plates.
It is also known to provide corrugated fins or ribs sandwiched between pairs of plates of a heat exchanger such as an oil cooler that act as a turbulator to increase the oil side heat transfer coefficient while having to accept an appreciable amount of oil side pressure drop. One known method of making such a construction is to physically insert a corrugated fin into the space between the plates after the plates have been manufactured. This is an extremely difficult process since the corrugated fin to be inserted between the plates is extremely thin and subject to deformation during the insertion process.
It is also known to provide beaded plates for a heat exchanger in which beads define a plurality of passageways between the plates for movement of a fluid therethrough to increase the surface area of conductive material available for heat transfer and to cause turbulence or mixing of the fluid carried between the plates. An example of such a heat exchanger is disclosed in U.S. Pat. No. 4,600,053. In this patent, each of the plates has a plurality of beads formed thereon with one plate having one distinct variety of beads and the other plate having another distinct variety of beads. The beads of the plates contact each other and are bonded together to force fluid to flow therearound. The beads are aligned in rows in which one row has an xe2x80x9cAxe2x80x9d pattern and the adjacent or next row has a xe2x80x9cBxe2x80x9d pattern in which the beads are aligned with spaces of the A pattern. The rows are repeated in an AB pattern in which the beads in the A rows are aligned longitudinally or downstream with each other and the beads in the B rows are aligned longitudinally or downstream with each other.
Current oil to water in-tank oil coolers require the insertion of a turbulator to enhance oil side heat transfer. These oil coolers require thick material for the plates to meet burst requirements due to minimal contact between the plates on the water side. Examples of such oil to water in-tank oil coolers are disclosed in U.S. Pat. Nos. 5,369,883 and 5,538,077. Both of these patents disclose an in-tank oil cooler with turbulators.
Although the above heat exchangers have worked well, it is desirable to eliminate the use of a turbulator between plates of a heat exchanger. It is also desirable to provide beaded plates for a heat exchanger having a repeating bead pattern stamped into the plate on both the oil and coolant sides to enhance heat transfer. It is further desirable to provide beaded plates for a heat exchanger that allow for thinner material to be used for the plates.
Accordingly, the present invention is a beaded plate for a heat exchanger including a plate having a generally planar first surface and opposed second surface. The beaded plate also a plurality of first beads extending generally perpendicular to the first surface of the plate and a plurality of second beads extending generally perpendicular to the second surface of the plate. The first beads have a generally arcuate end surface and the second beads have a generally planar end surface.
Also, the present invention is a method of making a beaded plate for a heat exchanger. The method includes the steps of providing a plate having a generally planar first surface and an opposed second surface. The method includes the step of forming a plurality of first beads to extend generally perpendicular to the first surface of the plate with a generally arcuate end surface and a plurality of second beads to extend generally perpendicular to the second surface of the plate with a generally planar end surface.
One advantage of the present invention is that a beaded plate for a heat exchanger such as an oil cooler is provided for a motor vehicle for cooling liquid oil. Another advantage of the present invention is that the beaded plate eliminates the need for a separate turbulator between plates for a heat exchanger such as an in-tank oil cooler. Yet another advantage of the present invention is that the beaded plate has a repeating bead pattern stamped into the plate on both the oil and coolant sides. Still another advantage of the present invention is that the beaded plate has a repeating bead pattern on the oil side that enhances heat transfer and a repeating bead pattern on the coolant side to provide structural integrity and enhance coolant side heat transfer. A further advantage of the present invention is that the beaded plate has beads on the oil side that mate with each other as do the beads on the water side. Yet a further advantage of the present invention is that the beaded plate has a bead pattern that alternates to produce a maximum amount of turbulence or mixing. Still a further advantage of the present invention is that a method of making a beaded plate for an oil cooler is provided which uses less material, parts and complexity for assembly. Another advantage of the present invention is that the beaded plate allows for a thinner material to be used for the plates.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.
FIG. 1 is a perspective view of a beaded plate, according to the present invention, illustrated in operational relationship with a heat exchanger for a motor vehicle.
FIG. 2 is a plan view of the beaded plate of FIG. 1.
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2.